Great job man!
You were faster than me!
I'll try to build my own version later (because I need to reorder some arduino and stuff to my new adress).
I'd be happy to see the hardware, some pics you know.

@Nairod785 note that you can only use keyboard commands with the leonardo, with uno, mega etc you have to do some sneaky re-flashing of the usb interface chip in order to emulate a keyboard. If you're ordering a new arduino it might be easier with a Leonardo.

As a suggestion for your code, it would be interesting if you could add a 'program' button for ring UIDs (enabled with pre-authorised master ring) and switch the code around a bit to grab the password from the ring?

Sounds cool. That way you could link 'allow authorisation' to UID and have the password grabbed from the ring so it's two part authentication. If you're really keen you could encrypt the stored password and have the arduino decrypt it.